Amphipods (Scuds, Side-Swimmers) as Food for Amphibians and Reptiles

Like sowbugs (isopods, pillbugs), Amphipods are crustaceans that feature prominently in natural diets of many reptiles and amphibians. They contain nutrients not found in insects, and are likely a rich source of calcium. Several species are easy to collect and breed in captivity, but, unlike sowbugs, they rarely attract much attention from hobbyists (please see the article below for information on breeding sowbugs). Whether you know them as Rock-Hoppers, Sand-Hoppers, Lawn Shrimp or any of the names above, one Amphipod or another likely makes its home near yours, and may be worth investigating as a food source for your pets.

Natural History

Amphipod diversity is astounding…over 7,000 species have been identified, and experts concede that they have no idea of the actual number in existence.

Found from pole to pole, Amphipods reach their greatest abundance in colder oceans. Most live in marine environments, but a number have colonized fresh water and land; of the known terrestrial species, 45% dwell in caves or other subterranean environments. They range in size from 0.8 to 1.6 inches long, and may be omnivorous, carnivorous or herbivorous.

Amphipods in Captive Diets

Amphipods are readily accepted by newts of all types, Mexican Axolotls, many turtles, and aquatic frogs such as African and Dwarf Clawed Frogs and Surinam Toads. Salamander larvae and carnivorous tadpoles relish smaller species.

They can also be offered to terrestrial salamanders and frogs; in these cases, confining the Amphipods to a bowl is usually the best feeding method. The Zoo Med Turtle Pier makes an ideal platform on which to present Amphipods to Fire-Bellied Toads and other semi-aquatic frogs; please see this article for further information.

I have also fed Amphipods to sunfishes, perch and other native and tropical species. The eager reactions exhibited by many fishes and herps are hard to describe, but very different than that given to their usual food items.

Precautions: Marine Species and Parasites

I avoid using marine Amphipods (or fish, for that matter) as a dietary staple for captive herps, focusing instead upon freshwater species. However, I’ve not had any problems using either as a supplement to regular diets.

The possibility of transferring parasites from wild-caught fresh water Amphipods has been raised (marine species would not likely be a concern in this regard), but I have not experienced this in my own or zoo collections. If you are concerned about parasites, consider captive-bred cultures or methylene blue pre-treatments; please write in for further information.

Collecting Amphipods

Fresh water and marine Amphipods are most easily collected by pulling a seine or hand net through shoreline aquatic plants or seaweed. I’ve also occasionally taken larger species in minnow traps baited with fish.

Beached seaweed at the high tide line is usually home to huge populations of terrestrial Amphipods collectively known as Rock Hoppers or Sand Hoppers (Taritrus spp.). Eel Grass beds along the USA’s eastern coast support Amphipods that resemble this unique marine plant in shape and color. One, Gammarus mucronatus, is large and quite interesting, and provided me with a great introduction to marine aquarium keeping decades ago.

Gammarus fasciatus, a fresh water Amphipod that reaches ½ inch or so in length, is sometimes common on fish farms. I believe this to be the species that I found in tropical fish shipments when I worked for an importer years ago. I saw the same or a similar Amphipod on fish farms in Florida and in aquatic plant greenhouses in NY. If you have access to such places, look into the possibility of doing some collecting, as G. fasciatus is hardy and easy to breed (please see below).

Keeping and Breeding Amphipods

Fresh-water Amphipods may be kept in a well-lit aquarium stocked with Elodea, algae, Java Moss and other aquatic vegetation. A corner filter will provide adequate filtration and aeration; strong currents should be avoided. Water quality may be managed as for tropical fishes (please write in for further information). A temperature range of 60-75 F suits most.

While dietary specialists exist, those Amphipods I’ve kept proved to have easily-satisfied appetites. Fish food flakes, shrimp pellets, spirulina disks, boiled kale and bits of fish were all accepted. A healthy growth of algae appears to be important to their survival as well.

Female Amphipods carry their 10-50 eggs in a brood pouch; depending upon the species, 4-6, or perhaps more, clutches may be produced each year.

Marine species can be kept as above; please write in if you need information on establishing a salt-water aquarium.

Amphipods as “Pets”

Amphipods are active, interesting creatures, and I thoroughly enjoy observing their behaviors. When established in an aquarium, they also perform useful scavenging services. Don’t be surprised if you find yourself keeping them for “their own sake”, and please be sure to write in to share your experiences.

8 comments

Have you experimented much with raising sand fleas? A species here (Megalorchestia californica) is very large and quite impressive looking. I collected a few but they all died off pretty quickly in the admittantly simple setup I tried using.(shallow damp sand, fed bits of fish food). The long ride home crammed in a small container may have done them in, however.

Nice to hear from you; I hope all is well. I’ve kept local species alive for some time after collecting, but just to use up as food, not to breed. Those here seem heat sensitive..even though they are in direct sun, most of their time seems to be spent beneath damp seaweed and debris. I transported them in cooler or cork earthworm keeper, and stored in a basement.

hey thanks for the info I found some smaller ones in my aquarium. they’ve been there for months never really that noticeable I’m pretty sure my guppies were making tasty snacks of all the small ones now all I have in my tank is cherry shrimp ponds snails and these guys and the population is booming it looks like a bunch of baby fleas all over but the biggest ones look almost like the shrimp they’ve even started to get some red coloration on their back I don’t know if they’re trying to blend in with the shrimp or what I do have plenty of Java fern for them to munch I was worried they would harm my shrimp they seem to be fine though they all seem to be playing together and getting along okay but I am breeding cherry shrimp could you see any issues with these guys and the shrimp both breeding and living in the same tank. I think this is the longest post ive ever made thank you so much for all the info

Thanks for the kind words. I’ve had them in with the same creatures you’re keeping without any problems, and they make great scavengers and food items for the fish. There are many species with different habits…always a chance they might snack on shrimp eggs but I’ve not seen or read of this. I’m wondering if the red color could be related to food showing through the body, as we see in some shrimp, or their being influenced by the diet…changing color in response to fish “color food” etc? They often go through population explosions, then times when you’ll see few. Please keep me posted, interested to hear how they do. A happy, healthy new year to you and yours, Frank

It’s nice to see someone taking scuds seriously. I get a kick out of them, and the ones I have are also outstanding at cleaning algae from new plants that may arrive with infestations of undesired algaes. The scuds do a better job than even snails, and no toxic dips or chemicals are needed.

My loaches, mainly kuhli types, as well as cories and some other bottom feeders love the darn things, and so the population in my tanks never gets out of hand. They have their own tank as well, so I always have some breeding. Interesting variations in colour, fun to watch them mating, they look like rodeo bronc riders in the mating process.

Pretty harmless, very useful, I wouldn’t be without them. And I have never seen them bother dwarf shrimp or their babies either, a few species of which have inhabited the same tanks as the scuds do. I suppose a very hungry scud might take a baby shrimp, but I think they have enough food that they don’t really go hunting for them.

Thank you Karen! I don’t much support where these guys are concerned….even at the zoo I had to battle for time and space to set them u. My experiences echo yours, and I also find them very interesting in their own right..hard to understand why folks do not pat attention to them. So much to learn also, and new species likely to surface nearly anywhere. I favor loaches and various cat fish as well..several of my weather loaches are in their 20’s, kuhlis i late teens!

Sorry for the double post.. I was cleaning up my browser pages and accidentally hit the post button again.

I wish I knew for certain just which species of amphipod I have. I have some pics but they’re not very clear. They tend to move suddenly, making a good pic difficult to get, and they are not very big, even full grown.

Maybe once I get a macro lens for my camera, I’ll manage some decent ones. Wish I could have got one of a pregnant female I saw the other day. She was so laden with eggs, she looked like a totally different creature. The newborns are hard to distinguish from other small beasties I also have, such as daphnia or moina. Once they get some size, their swimming patterns make it fairly easy to tell they are scuds but it takes a wee while for them to grow large enough to be sure that’s what they are.

Thanks for the interesting post…I’ve looked into ID’s a bit -very interesting and frustrating! In most cases ID relies upon analyzing structures too small to be seen..natural range, size and breeding behavior can be useful in narrowing the field. I’ve also kept a large marine species that is very common in eel grass beds in the Great South bay, Long Is, NY; less so now that eel grass is in decline. Very active, mimics eel grass in shape and color…eaten by many fishes but adults lived well with pipefish and smaller crabs, Enjoy and pl keep me posted, Frank

About Frank Indiviglio

Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.

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